This invention relates in general to two-stage control valves. In particular, this invention relates to an improved linear modular package for a two-stage control microvalve for use in a hydraulic fluid system such as an automatic transmission.
Internal combustion engines combust an air/fuel mixture within cylinders to drive pistons that rotatably turn a crankshaft generating drive torque. The drive torque may be transferred to a driveline of a vehicle, e.g., the wheels, via a transmission. The drive torque may also be translated or multiplied by one of a plurality of gear ratios of the transmission. The transmission may be coupled to the crankshaft via a torque converter. The transmission includes a plurality of components such as solenoid valves, clutches, and one or more planetary gear sets.
The solenoid valves may each include a solenoid and a valve. More specifically, the solenoid may convert electrical energy, e.g., current from a controller, into mechanical energy that opens or closes the valve mechanically. The transmission may also include servos that actuate one or more of the clutches. The clutches may engage one or more gears of the planetary gear sets.
The transmission also includes hydraulic fluid that controls one or more of the components. The hydraulic fluid is typically supplied to the transmission from a main pump. The transmission may include pressure control solenoid valves, shift solenoid valves, and/or flow control solenoid valves. The pressure control solenoid valves and the flow control solenoid valves control the pressure and flow of hydraulic fluid in the transmission, respectively. The shift solenoid valves, on the other hand, control components of the transmission, such as the servos, clutches, and gears, based on a pressure of the hydraulic fluid. Such valves can be relatively large and expensive to manufacture.
It would be desirable therefore, to provide an improved valve and actuator structure for a hydro-mechanical valve system, such as in a vehicle transmission.